Method of reducing staining of stannous in dentifrice compositions

ABSTRACT

Disclosed are methods for reducing the staining of dentifrice composition containing stannous comprising administering to a subject the dentifrice composition. The dentifrice composition is a dual phase dentifrice and is contained in physically separated compartments of a dentifrice dispenser. The first dentifrice composition comprises an effective amount of one or more linear polyphosphates having an average chain length of about 4 or more and has a total water content of up to about 20%. The second dentifrice composition comprises an effective amount of stannous ions. The molar ratio of polyphosphate anion to stannous ion is from about 0.2:1 to about 5:1 and the efficacy of the stannous ion in the dentifrice is not reduced by the polyphosphate. The dentifrice composition may alternatively be a single phase dentifrice. The single phase dentifrice will comprise an effective amount of one or more linear polyphosphates having an average chain length of about 4 or more and an effective amount of a stannous ion. The single phase dentifrice has a total water content of up to about 20%, the stannous ion is not delivered from stannous fluoride, a molar ratio of polyphosphate anion to stannous ion is from about 0.2:1 to about 5:1, and the efficacy of the stannous ion in the dentifrice is not reduced by the polyphosphate.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.10/039,620, filed Oct. 24, 2001, now U.S. Pat. No. 6,667,027 which is adivisional of U.S. application Ser. No. 09/451,420 filed Nov. 30, 1999and now U.S. Pat. No. 6,350,436, which is a continuation-in-part ofapplication Ser. No. 09/203,216, filed Nov. 30, 1998, abandoned, whichis a continuation-in-part of application Ser. No. 08/754,577, filed Nov.21, 1996, now U.S. Pat. No. 5,939,052.

BACKGROUND OF THE INVENTION

The present invention relates to a method of reducing the stainingcaused by dentifrice compositions containing stannous. The presentinventors have discovered that the use of a polyphosphate will help toreduce the staining that is associated with stannous. It has also beendiscovered that certain polyphosphates, in particular, linearpolyphosphates with average chain lengths of about 4 or more will reducethe staining of the stannous without reducing the efficacy of thestannous.

The term “stannous” as used herein, is defined to mean the stannous thatis in a dentifrice. It may refer to the stannous ions that are providedby a stannous salt. Stannous salts which contain stannous ions arecommonly known. Stannous has been found to provide antigingivitis andantiplaque benefits. In addition stannous may also help to improvebreath and reduce sensitivity. Dentifrices containing stannous are alsoknown to be astringent and to cause staining on a subject's toothsurface. Some previous attempts to reduce the staining of stannous havebeen successful. However, once the staining was reduced, the efficacy ofthe stannous was also significantly reduced. For example, when apyrophosphate, diphosphonate (AHP), and tripolyphosphate are used in adentifrice with stannous, the efficacy of the stannous is reduced. Thisreduction in efficacy occurs even if the stannous is in a separate phasefrom the pyrophosphate, diphosphonate, and tripolyphosphate. One havingordinary skill in the art would assume that a polyphosphate having anaverage chain length of about 4 or more would behave similarly to thepyrophosphate. The present inventors have found that an unexpectedresult occurs with the polyphosphate as it reduces the staining but doesnot significantly reduce the efficacy of the stannous.

To improve consumer acceptance and compliance with the use ofdentifrices containing stannous, a method is needed to reduce the amountof staining that occurs on a subjects teeth while still maintaining theefficacy of the stannous.

Therefore, it is an object of the present invention to provide a methodof reducing staining of dentifrice composition containing stannous byadministering to a subject a stable dentifrice compositions comprisingtwo dentifrice compositions which are contained in physically separatedcompartments, allowing maximum fluoride and polyphosphate delivery tothe oral cavity. The first dentifrice composition comprises apolyphosphate and has a limited total water content while the secondcomposition comprises stannous ions. It is also an object of the presentinvention to provide a method of reducing staining of dentifricecomposition containing stannous by administering to a subject a stablesingle phase dentifrice composition. The composition will comprise apolyphosphate, a stannous ion delivered from a source other thanstannous fluoride, and have a limited total water content.

These and other objects of the present invention will become readilyapparent from the detailed description which follows.

All percentages used herein are by weight of the dentifrice composition,unless otherwise specified. The ratios used herein are molar ratios ofthe overall composition, unless otherwise specified. All measurementsare made at 25° C., unless otherwise specified.

SUMMARY OF THE INVENTION

The present invention relates methods for reducing the staining ofdentifrice composition containing stannous comprising administering to asubject the dentifrice composition. The dentifrice composition is a dualphase dentifrice and is contained in physically separated compartmentsof a dentifrice dispenser. The first dentifrice composition comprises aneffective amount of one or more linear polyphosphates having an averagechain length of about 4 or more and has a total water content of up toabout 20%. The second dentifrice composition comprises an effectiveamount of stannous ions. The molar ratio of polyphosphate anion tostannous ion is from about 0.2:1 to about 5:1 and the efficacy of thestannous ion in the dentifrice is not significantly reduced by thepolyphosphate. The dentifrice composition may alternatively be a singlephase dentifrice. The single phase dentifrice will comprise an effectiveamount of one or more linear polyphosphates having an average chainlength of about 4 or more and an effective amount of a stannous ion. Thesingle phase dentifrice has a total water content of up to about 20%,the stannous ion is not delivered from stannous fluoride, a molar ratioof polyphosphate anion to stannous ion is from about 0.2:1 to about 5:1,and the efficacy of the stannous ion in the dentifrice is not reduced bythe polyphosphate.

DETAILED DESCRIPTION OF THE INVENTION

The dentifrice composition of the present invention may be in the formof a toothpaste or dentifrice. The term “dentifrice”, as used herein,means paste, gel, or liquid formulations unless otherwise specified. Thedentifrice composition may be in any desired form, such as deep striped,surface striped, mulitlayered, having the gel surrounding the paste, orany combination thereof.

If a dual phase dentifrice is desired, each dentifrice composition willbe contained in a physically separated compartment of a dispenser anddispensed side-by-side. The term “dispenser”, as used herein, means anypump, tube, or container suitable for dispensing toothpaste.

The dentifrice composition may be a single phase dentifrice compositionor may be a combination of the two or more dentifrice compositions. Thedentifrice composition is a product, which in the ordinary course ofadministration, is not intentionally swallowed for purposes of systemicadministration of particular therapeutic agents, but is rather retainedin the oral cavity for a time sufficient to contact substantially all ofthe tooth surfaces and/or oral tissues for purposes of oral activity.

The term “aqueous carrier” as used herein means any safe and effectivematerials for use in the compositions of the present invention. Suchmaterials include fluoride ion sources, tartar control agents,antibacterial agents, abrasive polishing materials, peroxide sources,alkali metal bicarbonate salts, thickening materials, humectants, water,buffering agents, surfactants, titanium dioxide, flavor system,sweetening agents, coloring agents, and mixtures thereof.

The term “reduced” as used herein means a statistically significantreduction. Therefore, reducing the staining of stannous means that theamount of stain is statistically significantly reduced from a control.Not reducing the efficacy of the stannous means where the efficacy ofthe stannous is not statistically significantly reduced from a control.A control product containing stannous may be Crest Gum Care.

The present compositions comprise essential components, as well asoptional components. The essential and optional components of thecompositions of the present invention are described in the followingparagraphs.

Stannous Ions

The present invention includes a stannous ion. The stannous iongenerally comes from a stannous salt that is added to a dentifrice.Stannous has been found to help in the reduction gingivitis, plaque,sensitivity, and improved breath benefits. The stannous in a dentifricecomposition will provide efficacy to a subject using the dentifrice.“Efficacy” is defined as a noticeable amount of reduction in gingivitisas measured by the Plaque Glycolysis Regrowth Model (PGRM). The presentinventors have found a way to prevent the efficacy of the stannous frombeing reduced, while reducing the staining caused by the stannous.Specifically, the efficacy of the stannous is not reduced by thepolyphosphate even though the polyphosphate reduces the staining of thestannous. Therefore, the efficacy of the stannous is maintained at alevel found in dentifrices containing stannous which are known forreducing gingivitis, such as Crest Gum Care.

The staining of the tooth surface typically caused by stannous ismeasured on the clinical stain index known as the Lobene stain index.The staining may also be measured on the clinical stain index call theMeckel stain index. The present inventors have found that the staintypically caused by the stannous is reduced by the polyphosphate. Asstated, the staining caused by the stannous is reduced but noteliminated. Therefore, the amount of stain resulting from the dentifricecompositions of the present invention is significantly lower than theamount of staining found in typical dentifrices containing stannous,such as Crest Gum Care.

Stannous ions are found in the dentifrice composition in an effectiveamount. An effective amount is defined as from about 3,000 ppm to about15,000 ppm. Below 3,000 ppm stannous the efficacy of the stannous is notsignificant. Preferably, the stannous ion is present in an amount ofabout 5,000 ppm to about 13,000 ppm and more preferably from about 7,000ppm to about 10,000 ppm. This is the total amount of stannous ion thatis delivered to the tooth surface.

Dentifrices containing stannous salts, particularly stannous fluorideand stannous chloride, are described in U.S. Pat. No. 5,004,597 toMajeti et al., incorporated herein in its entirety. Other descriptionsof stannous salt dentifrices are found in U.S. Pat. No. 5,578,293. Thepreferred stannous salts are stannous fluoride and stannous chloridedihydrate. Other stannous salts include stannous acetate. The combinedstannous salts will be present in an amount of from about 0.25% to about11%, by weight of the final composition. Preferably, the stannous saltsare present in an amount of from about 0.5 to about 7%, more preferablyfrom about 1% to about 5%, and most preferably from about 1.5% to about3%.

Polyphosphate Source

The present invention includes a polyphosphate source. Polyphosphatesare known to help retard calculus formation. However, it is also knownthat polyphosphates with an average chain length greater than about 4will also react with ionic fluoride in oral compositions at ambienttemperature and produce monofluorophosphate ions, in addition toaltering the pH of the composition. This reaction compromises theefficacy of the oral composition and its ability to provide stable ionicfluoride and polyphosphate to the oral surfaces. It is also known thatto have stable polyphosphate, the total water content of the dentifricecomposition must be controlled to reduce the hydrolysis of thepolyphosphate.

A polyphosphate is generally understood to consist of two or morephosphate molecules arranged primarily in a linear configuration,although some cyclic derivatives may be present. Although pyrophosphatesare a polyphosphate, the polyphosphates desired are those having aroundfour or more phosphate molecules. The pyrophosphates are discussedseparately. The inorganic polyphosphate salts desired includetetrapolyphosphate and hexametaphosphate, among others. Polyphosphateslarger than tetrapolyphosphate usually occur as amorphous glassymaterials. Preferred in this invention are the linear “glassy”polyphosphates having the formula:XO(XPO₃)_(n)Xwherein X is sodium or potassium and n averages from about 6 to about125. Preferred are polyphosphates manufactured by FMC Corporation whichare commercially known as Sodaphos (n≈6), Hexaphos (n≈13), and Glass H(n≈21). These polyphosphates may be used alone or in an combinationthereof.

The phosphate sources are described in more detail in Kirk & Othmer,Encyclopedia of Chemical Technology, Fourth Edition, Volume 18,Wiley-Interscience Publishers (1996), incorporated herein by referencein its entirety, including all references incorporated into Kirk &Othmer. The amount of polyphosphate required is an effective amountwhich will reduce the staining of the stannous. The effective amountwill also reduce tartar. An effective amount of a polyphosphate sourcewill typically be from about 1% to about 20%, preferably from about 2%to about 17%, more preferably from about 4% to about 15%, and mostpreferably from about 5% to about 13%, by weight of the total dentifricecomposition.

For the polyphosphate to have a beneficial effect on reducing thestaining of the stannous, the ratio of total moles of polyphosphateanion to total moles of stannous ion should also be controlled. Thismolar ratio of polyphosphate anion to stannous ion is from about 0.2:1to about 5:1, preferably from about 0.5:1 to about 3:1, more preferablyfrom about 0.6:1 to about 2:1, and most preferably from about 0.7:1 toabout 1:1.

Aqueous Carriers

In preparing the present compositions, it is desirable to add one ormore aqueous carriers to the compositions. Such materials are well knownin the art and are readily chosen by one skilled in the art based on thephysical and aesthetic properties desired for the compositions beingprepared. Aqueous carriers typically comprise from about 40% to about99%, preferably from about 70% to about 98%, and more preferably fromabout 90% to about 95%, by weight of the dentifrice composition.

Total Water Content

Water employed in the preparation of commercially suitable oralcompositions should preferably be of low ion content and free of organicimpurities. In the dentifrice composition, water will generally comprisefrom about 5% to about 70%, and preferably from about 10% to about 50%,by weight of the composition herein. This water content may be in asingle phase dentifrice or may be the resulting total water content of adual phase dentifrice. If the dentifrice composition comprises thepolyphosphate having an average chain length of about 4 or more, thedentifrice composition or phase containing the polyphosphate willcomprise a lower level of water, generally from about 0% up to about 20%total water. Preferably, the total water content is from about 2% toabout 20%, more preferably from about 4% to about 15%, and mostpreferably from about 5% to about 12%, by weight of the dentifricecomposition. The amounts of water include the free water which is addedplus that which is introduced with other materials, such as withsorbitol, silica, surfactant solutions, and/or color solutions.

Fluoride Ion Source

The dentifrice compositions of the present invention may incorporate asoluble fluoride source capable of providing free fluoride ions. Solublefluoride ion sources include sodium fluoride, stannous fluoride, indiumfluoride, and sodium monofluorophosphate. Stannous fluoride is the mostpreferred soluble fluoride ion source. This ingredient may serve as boththe stannous ion and fluoride ion source. If a polyphosphate having achain length of about 4 or more is in the same phase as the fluoride ionsource, the preferred fluoride ion source is sodium monofluorophosphate.This is because sodium monofluorophosphate has been found to be morestable than other fluoride sources in the presence of a polyphosphatehaving an average chain length of about 4 or more. Norris et al., U.S.Pat. No. 2,946,725, issued Jul. 26, 1960, and Widder et al., U.S. Pat.No. 3,678,154 issued Jul. 18, 1972, disclose such fluoride ion sourcesas well as others. Both patents are incorporated herein by reference intheir entirety.

The present compositions may contain a soluble fluoride ion sourcecapable of providing from about 50 ppm to about 3500 ppm, and preferablyfrom about 500 ppm to about 3000 ppm of free fluoride ions. To deliverthe desired amount of fluoride ions, stannous fluoride may be present inthe total dentifrice composition at an amount of from about 0.1% toabout 5%, preferably from about 0.2% to about 1%, and more preferablyfrom about 0.3 to about 0.6%, by weight of the total dentifricecomposition.

Buffering Agent

The present compositions may contain a buffering agent. Bufferingagents, as used herein, refer to agents that can be used to adjust thepH of the compositions to a range of about pH 3.0 to about pH 10. Thephase of the dentifrice containing stannous will typically have a slurrypH of from about 3.0 to about 5.5, preferably from about 3.25 to about5, and more preferably from about 3.4 to about 4.5. The phase of thedentifrice containing the polyphosphate will typically have a slurry pHof from about 4.0 to about 10, preferably from about 4.5 to about 8, andmore preferably from about 5.0 to about 7.0. is A dentifrice containingboth stannous and polyphosphate in a single phase will typically have apH of from about 4 to about 7, preferably from about 4.5 to about 6, andmore preferably from about 5 to about 5.5.

The buffering agents include alkali metal hydroxides, carbonates,sesquicarbonates, borates, silicates, phosphates, imidazole, andmixtures thereof. Specific buffering agents include monosodiumphosphate, trisodium phosphate, sodium benzoate, benzoic acid, sodiumhydroxide, potassium hydroxide, alkali metal carbonate salts, sodiumcarbonate, imidazole, pyrophosphate salts, citric acid, and sodiumcitrate. Buffering agents are used at a level of from about 0.1% toabout 30%, preferably from about 1% to about 10%, and more preferablyfrom about 1.5% to about 3%, by weight of the present composition.

Anticalculus Agents

Optional agents to be used in place of or in combination with thepolyphosphate include such materials known to be effective in reducingcalcium phosphate mineral deposition related to calculus formation.Agents included are pyrophosphates, tripolyphosphates, synthetic anionicpolymers [including polyacrylates and copolymers of maleic anhydride oracid and methyl vinyl ether (e.g., Gantrez), as described, for example,in U.S. Pat. No. 4,627,977, to Gaffar et al., the disclosure of which isincorporated herein by reference in its entirety; as well as, e.g.,polyamino propane sulfonic acid (AMPS)], zinc citrate trihydrate,diphosphonates (e.g., EHDP; AHP), polypeptides (such as polyaspartic andpolyglutamic acids), and mixtures thereof.

Abrasive Polishing Materials

An abrasive polishing material may also be included in the toothpastecompositions. The abrasive polishing material contemplated for use inthe compositions of the present invention can be any material which doesnot excessively abrade dentin. Typical abrasive polishing materialsinclude silicas including gels and precipitates; aluminas; phosphatesincluding orthophosphates, polymetaphosphates, and pyrophosphates; andmixtures thereof. Specific examples include dicalcium orthophosphatedihydrate, calcium pyrophosphate, tricalcium phosphate, calciumpolymetaphosphate, insoluble sodium polymetaphosphate, hydrated alumina,beta calcium pyrophosphate, calcium carbonate, and resinous abrasivematerials such as particulate condensation products of urea andformaldehyde, and others such as disclosed by Cooley et al in U.S. Pat.No. 3,070,510, issued Dec. 25, 1962, incorporated herein by reference.Mixtures of abrasives may also be used. If the dentifrice composition orparticular phase comprises a polyphosphate having an average chainlength of about 4 or more, calcium containing abrasives and alumina arenot preferred abrasives. The most preferred abrasive is silica.

Silica dental abrasives of various types are preferred because of theirunique benefits of exceptional dental cleaning and polishing performancewithout unduly abrading tooth enamel or dentine. The silica abrasivepolishing materials herein, as well as other abrasives, generally havean average particle size ranging between about 0.1 to about 30 microns,and preferably from about 5 to about 15 microns. The abrasive can beprecipitated silica or silica gels such as the silica xerogels describedin Pader et al., U.S. Pat. No. 3,538,230, issued Mar. 2, 1970, andDiGiulio, U.S. Pat. No. 3,862,307, issued Jan. 21, 1975, bothincorporated herein by reference. Preferred are the silica xerogelsmarketed under the trade name “Syloid” by the W. R. Grace & Company,Davison Chemical Division. Also preferred are the precipitated silicamaterials such as those marketed by the J. M. Huber Corporation underthe trade name, “Zeodent”, particularly the silica carrying thedesignation “Zeodent 119”. The types of silica dental abrasives usefulin the toothpastes of the present invention are described in more detailin Wason, U.S. Pat. No. 4,340,583, issued Jul. 29, 1982, incorporatedherein by reference. Silica abrasives are also described in Rice, U.S.Pat. Nos. 5,589,160; 5,603,920; 5,651,958; 5,658,553; and 5,716,601;herein incorporated by reference. The abrasive in the toothpastecompositions described herein is generally present at a level of fromabout 6% to about 70% by weight of the composition. Preferably,toothpastes contain from about 10% to about 50% of abrasive, by weightof the dentifrice composition.

Peroxide Source

The present invention may include a peroxide source in the composition.The peroxide source is selected from the group consisting of hydrogenperoxide, calcium peroxide, urea peroxide, and mixtures thereof. Thepreferred peroxide source is calcium peroxide. The following amountsrepresent the amount of peroxide raw material, although the peroxidesource may contain ingredients other than the peroxide raw material. Thepresent composition may contain from about 0.01% to about 10%,preferably from about 0.1% to about 5%, more preferably from about 0.2%to about 3%, and most preferably from about 0.3% to about 0.8% of aperoxide source, by weight of the dentifrice composition.

Alkali Metal Bicarbonate Salt

The present invention may also include an alkali metal bicarbonate salt.Alkali metal bicarbonate salts are soluble in water and unlessstabilized, tend to release carbon dioxide in an aqueous system. Sodiumbicarbonate, also known as baking soda, is the preferred alkali metalbicarbonate salt. The alkali metal bicarbonate salt also functions as abuffering agent. The present composition may contain from about 0.5% toabout 50%, preferably from about 0.5% to about 30%, more preferably fromabout 2% to about 20%, and most preferably from about 5% to about 18% ofan alkali metal bicarbonate salt, by weight of the dentifricecomposition.

Additional Aqueous Carriers

The present invention compositions in the form of toothpastes, typicallycontain some thickening material or binders to provide a desirableconsistency. Preferred thickening agents are carboxyvinyl polymers,carrageenan, hydroxyethyl cellulose, and water soluble salts ofcellulose ethers such as sodium carboxymethylcellulose and sodiumhydroxyethyl cellulose. Natural gums such as gum karaya, xanthan gum,gum arabic, and gum tragacanth can also be used. Colloidal magnesiumaluminum silicate or finely divided silica can be used as part of thethickening agent to further improve texture. Thickening agents can beused in an of amount from about 0.1% to about 15%, by weight of thedentifrice composition.

Another optional component of the compositions desired herein is ahumectant. The humectant serves to keep toothpaste compositions fromhardening upon exposure to air and certain humectants can also impartdesirable sweetness of flavor to toothpaste compositions. Suitablehumectants for use in the invention include glycerin, sorbitol,polyethylene glycol, propylene glycol, xylitol, and other ediblepolyhydric alcohols. The humectant generally comprises from about 0% to70%, and preferably from about 15% to 55%, by weight of the composition.

The present compositions may also comprise surfactants, also commonlyreferred to as sudsing agents. Suitable surfactants are those which arereasonably stable and foam throughout a wide pH range. The surfactantmay be anionic, nonionic, amphoteric, zwitterionic, cationic, ormixtures thereof. Anionic surfactants useful herein include thewater-soluble salts of alkyl sulfates having from 8 to 20 carbon atomsin the alkyl radical (e.g., sodium alkyl sulfate) and the water-solublesalts of sulfonated monoglycerides of fatty acids having from 8 to 20carbon atoms. Sodium lauryl sulfate and sodium coconut monoglyceridesulfonates are examples of anionic surfactants of this type. Othersuitable anionic surfactants are sarcosinates, such as sodium lauroylsarcosinate, taurates, sodium lauryl sulfoacetate, sodium lauroylisethionate, sodium laureth carboxylate, and sodium dodecylbenzenesulfonate. Mixtures of anionic surfactants can also be employed.Many suitable anionic surfactants are disclosed by Agricola et al., U.S.Pat. No. 3,959,458, issued May 25, 1976, incorporated herein in itsentirety by reference. Nonionic surfactants which can be used in thecompositions of the present invention can be broadly defined ascompounds produced by the condensation of alkylene oxide groups(hydrophilic in nature) with an organic hydrophobic compound which maybe aliphatic or alkyl-aromatic in nature. Examples of suitable nonionicsurfactants include poloxamers (sold under trade name Pluronic),polyoxyethylene, polyoxyethylene sorbitan esters (sold under trade nameTweens), Polyoxyl 40 hydrogenated castor oil, fatty alcohol ethoxylates,polyethylene oxide condensates of alkyl phenols, products derived fromthe condensation of ethylene oxide with the reaction product ofpropylene oxide and ethylene diamine, ethylene oxide condensates ofaliphatic alcohols, long chain tertiary amine oxides, long chaintertiary phosphine oxides, long chain dialkyl sulfoxides, and mixturesof such materials. The nonionic surfactant poloxamer 407 is one of themost preferred surfactant because the poloxamer has been discovered tohelp reduce the astringency of the stannous. The amphoteric surfactantsuseful in the present invention can be broadly described as derivativesof aliphatic secondary and tertiary amines in which the aliphaticradical can be a straight chain or branched and wherein one of thealiphatic substituents contains from about 8 to about 18 carbon atomsand one contains an anionic water-solubilizing group, e.g., carboxylate,sulfonate, sulfate, phosphate, or phosphonate. Other suitable amphotericsurfactants are betaines, specifically cocamidopropyl betaine. Mixturesof amphoteric surfactants can also be employed. Many of these suitablenonionic and amphoteric surfactants are disclosed by Gieske et al., U.S.Pat. No. 4,051,234, issued Sep. 27, 1977, incorporated herein byreference in its entirety. The present composition typically comprisesone or more surfactants each at a level of from about 0.25% to about12%, preferably from about 0.5% to about 8%, and most preferably fromabout 1% to about 6%, by weight of the composition.

Titanium dioxide may also be added to the present composition. Titaniumdioxide is a white powder which adds opacity to the compositions.Titanium dioxide generally comprises from about 0.25% to about 5%, byweight of the composition.

Coloring agents may also be added to the present composition. Thecoloring agent may be in the form of an aqueous solution, preferably 1%coloring agent in a solution of water. Color solutions generallycomprise from about 0.01% to about 5%, by weight of the composition.

A flavor system can also be added to the compositions. Suitableflavoring components include oil of wintergreen, oil of peppermint, oilof spearmint, clove bud oil, menthol, anethole, methyl salicylate,eucalyptol, cassia, 1-menthyl acetate, sage, eugenol, is parsley oil,oxanone, alpha-irisone, marjoram, lemon, orange, propenyl guaethol,cinnamon, vanillin, ethyl vanillin, heliotropine, 4-cis-heptenal,diacetyl, methyl-para-tert-butyl phenyl acetate, and mixtures thereof.Coolants may also be part of the flavor system. Preferred coolants inthe present compositions are the paramenthan carboxyamide agents such asN-ethyl-p-menthan-3-carboxamide (known commercially as “WS-3”) andmixtures thereof. A flavor system is generally used in the compositionsat levels of from about 0.001% to about 5%, by weight of thecomposition.

Sweetening agents can be added to the compositions. These includesaccharin, dextrose, sucrose, lactose, xylitol, maltose, levulose,aspartame, sodium cyclamate, D-tryptophan, dihydrochalcones, acesulfame,and mixtures thereof. Various coloring agents may also be incorporatedin the present invention. Sweetening agents and coloring agents aregenerally used in toothpastes at levels of from about 0.005% to about5%, by weight of the composition.

The present invention may also include other agents, such asantimicrobial agents. Included among such agents are water insolublenon-cationic antimicrobial agents such as halogenated diphenyl ethers,phenolic compounds including phenol and its homologs, mono andpoly-alkyl and aromatic halophenols, resorcinol and its derivatives,bisphenolic compounds and halogenated salicylanilides, benzoic esters,and halogenated carbanilides. The water soluble antimicrobials includequaternary ammonium salts and bis-biquanide salts, among others.Triclosan monophosphate is an additional water soluble antimicrobialagent. The quaternary ammonium agents include those in which one or twoof the substitutes on the quaternary nitrogen has a carbon chain length(typically alkyl group) from about 8 to about 20, typically from about10 to about 18 carbon atoms while the remaining substitutes (typicallyalkyl or benzyl group) have a lower number of carbon atoms, such as fromabout 1 to about 7 carbon atoms, typically methyl or ethyl groups.Dodecyl trimethyl ammonium bromide, tetradecylpyridinium chloride,domiphen bromide, N-tetradecyl-4-ethyl pyridinium chloride, dodecyldimethyl (2-phenoxyethyl) ammonium bromide, benzyl dimethylstearylammonium chloride, cetyl pyridinium chloride, quaternized5-amino-1,3-bis(2-ethyl-hexyl)-5-methyl hexa hydropyrimidine,benzalkonium chloride, benzethonium chloride and methyl benzethoniumchloride are examplary of typical quaternary ammonium antibacterialagents. Other compounds are bis[4-(R-amino)-1-pyridinium] alkanes asdisclosed in U.S. Pat. No. 4,206,215, issued Jun. 3, 1980, to Bailey,incorporated herein by reference. Other antimicrobials such as copperbisglycinate, copper glysinate, zinc citrate, and zinc lactate may alsobe included. Also useful are enzymes, including endoglycosidase, papain,dextranase, mutanase, and mixtures thereof. Such agents are disclosed inU.S. Pat. No. 2,946,725, Jul. 26, 1960, to Norris et al. and in U.S.Pat. No. 4,051,234, Sep. 27, 1977 to Gieske et al., incorporated hereinby reference. Specific antimicrobial agents include chlorhexidine,triclosan, triclosan monophosphate, and flavor oils such as thymol.Triclosan and other agents of this type are disclosed in Parran, Jr. etal., U.S. Pat. No. 5,015,466, issued May 14, 1991, and U.S. Pat. No.4,894,220, Jan. 16, 1990 to Nabi et al., incorporated herein byreference. The water insoluble antimicrobial agents, water solubleagents, and enzymes may be present in either the first or seconddentifrice compositions. The quaternary ammonium agents, stannous salts,and substituted guanidines are preferably present in the seconddentifrice composition. These agents may be present at levels of fromabout 0.01% to about 1.5%, by weight of the dentifrice composition.

The dentifrice compositions may be a paste, gel, or any configuration orcombination thereof. If a dual phase dentifrice is desired, the firstand second dentifrice compositions will be physically separated in adentifrice dispenser. It is generally preferred that the firstdentifrice composition be a paste and the second dentifrice compositionbe a gel. The dispenser may be a tube, pump, or any other containersuitable for dispensing toothpaste. Dual compartment packages suitablefor this purpose are described in U.S. Pat. No. 4,528,180, issued Jul.9, 1985; U.S. Pat. Nos. 4,687,663, issued Aug. 18, 1987; and 4,849,213,issued Jul. 18, 1989, all to Shaeffer, all incorporated herein in theirentirety. The dispenser will deliver approximately equal amounts of eachdentifrice composition through an opening. The compositions may intermixonce dispensed. Alternatively, the oral formulation may be deliveredfrom a kit containing two separate dispensers which are used to delivertwo dentifrice compositions that are both used simultaneously.

Method of Treatment

The present invention relates to a method of reducing the stainingcaused by dentifrice composition containing stannous. Each subject mayhave a different level of staining that occurs. A method of reducing thestaining caused by dentifrice compositions containing stannous comprisesadministering to the subject the claimed dentifrice compositions. Themethod may also include preparing a dentifrice composition containingstannous and contacting the dentifrice composition with tooth surfacesof a subject. Administering to the subject is defined as having thedentifrice composition contact the tooth surfaces of the subject bybrushing with the dentifrice or rinsing with a dentifrice slurry. Thesubject may be any person or lower animal who uses the dentifrice.

EXAMPLES & METHOD OF MANUFACTURING

The following examples further describe and demonstrate embodimentswithin the scope of the present invention. These examples are givensolely for the purpose of illustration and are not to be construed aslimitations of the present invention as many variations thereof arepossible without departing from the spirit and scope.

Example I

First Dentifrice Composition Second Dentifrice Composition IngredientWt. % Ingredient Wt. % Carboxymethycellulose 0.500 SodiumHydroxide^((b)) 1.000 Water 2.768 Color 0.300 Flavor 1.00 Water 21.840Glycerin 36.432 Flavor 1.000 Polyethylene Glycol 1.500 Glycerin 28.992Propylene Glycol 8.00 Sodium Gluconate 4.160 Sodium LaurylSulphate^((a)) 4.00 Stannous Chloride 3.000 Silica 28.0 Silica 23.000Benzoic Acid 0.60 Sodium Saccharin 0.30 Sodium Benzoate 0.600 Poloxamer15.500 Sodium Saccharin 0.30 Stannous Fluoride 0.908 Titanium Dioxide1.000 Xanthan Gum 0.30 Glass H Polyphosphate 15.00 ^((a))27.9% solution^((b))50% solution

Example II

First Dentifrice Composition Second Dentifrice Composition IngredientWt. % Ingredient Wt. % Carboxymethycellulose 0.50 Sodium Hydroxide^((b))0.350 Water 2.768 Color 0.300 Flavor 1.00 Water 21.742 Glycerin 32.200Flavor 1.000 Benzoic Acid 0.600 Glycerin 30.900 Propylene Glycol 8.000Sodium Gluconate 4.300 Sodium Lauryl Sulphate^((a)) 8.00 StannousChloride 1.700 Silica 19.232 Silica 23.000 Polyoxyl 40 2.50 SodiumSaccharin 0.30 Polyoxyethylene 0.500 Stannous Fluoride 0.908 SodiumSaccharin 0.30 Poloxamer 407 15.500 Titanium Dioxide 1.0 Xanthan Gum0.30 Glass H Polyphosphate 21.00 Polyethylene Glycol 1.500 SodiumBenzolate 0.600 ^((a))27.9% solution ^((b))50% solution

Example III

First Dentifrice Composition Second Dentifrice Composition IngredientWt. % Ingredient Wt. % Carboxymethycellulose 0.50 Stannous Chloride1.200 Water 4.500 Color 0.300 Flavor 1.00 Water 21.840 Glycerin 32.200Flavor 1.000 Polyoxyethylene 0.500 Glycerin 33.032 Propylene Glycol10.000 Sodium Gluconate 2.420 Sodium Lauryl Sulphate^((a)) 6.000 SodiumHydroxide^((b)) 0.500 Silica 25.000 Silica 23.000 Poloxamer 407 3.000Sodium Saccharin 0.30 Sodium Benzoate 0.600 Poloxamer 15.500 SodiumSaccharin 0.300 Stannous Fluoride 0.908 Titanium Dioxide 1.000 XanthanGum 0.300 Glass H Polyphosphate 12.00 Polyethylene Glycol 2.500 BenzoicAcid 0.600 ^((a))27.9% solution ^((b))50% solution

The first dentifrice compositions are prepared as follows. Add thewater, sodium benzoate and saccharin to a mixing vessel. Dispersecarboxymethyl cellulose, xanthan gum and polyoxyethylene in glycerin.Add this glycerin slurry to the mixing vessel, mixing well and heatingto at least 40° C. Dissolve the benzoic acid in a mixture of flavor,propylene glycol, poloxamer, sodium lauryl sulphate and polyethyleneglycol, then add to the mixing vessel. Next add titanium dioxide andsilica. Mix well. Cool the mixing vessel to less than 30° C. and add thepolyphosphate. Mix until homogeneous.

The second dentifrice compositions are prepared as follows. Add water,color, and glycerin to the main mix vessel and heat to at least 50° C.Add the sodium gluconate and mix until completely dissolved. Addstannous fluoride and mix until completely dissolved. Add stannouschloride and mix until completely dissolved. Add sodium hydroxide,saccharin and silica and mix well. Add poloxamer and flavor and mixuntil poloxamer dissolves. Cool batch to less than 30° C.

Example IV

Ingredient Wt. % Water 5.000 Flavor 1.000 Glycerin 34.200 Poloxamer 4076.000 Stannous Chloride 2.000 Sodium Lauryl Sulphate^((a)) 6.000 Silica23.000 Carboxymethyl cellulose 0.500 Propylene Glycol 8.000 SodiumGluconate 2.400 Sodium Saccharin 0.400 Titanium Dioxide 1.000 XanthanGum 0.300 Glass H 8.000 Polyethylene Glycol 2.000 Polyoxyethylene 0.200^((a))27.9% solution ^((b))50% solution

Example IV is prepared as follows. Add the water and saccharin to amixing vessel and heat to at least 50° C. Add the sodium gluconate andmix until completely dissolved. Add stannous chloride and mix untilcompletely dissolved. Add sodium hydroxide and mix until neutralizationis complete. Disperse carboxymethyl cellulose, xanthan gum andpolyoxyethylene in glycerin. Add this glycerin slurry to the mixingvessel, mixing well. Combine together: flavor, propylene glycol,poloxamer, sodium lauryl sulphate and polyethylene glycol, then add tothe mixing vessel. Next add titanium dioxide and silica. Mix well. Coolthe mixing vessel to less than 30° C. and add the polyphosphate. Mixuntil homogeneous.

1. A single phase dentifrice composition comprising: a. an effectiveamount of one or more linear polyphosphates having an average chainlength of about 4 or more as the sole anti-calculus agent(s), whereinsaid polyphosphate(s) is water soluble and susceptible to hydrolysis; b.an effective amount of a stannous ion source; and c. a total watercontent of up to about 20% by weight of the composition, wherein thesingle phase dentifrice composition has a molar ratio of polyphosphateanion to stannous ion of from about 0.2:1 to about 5:1, wherein thestannous ion source comprises a stannous salt other than stannousfluoride or stannous monofluorophosphate, and the efficacy of thestannous ion in the dentifrice is not reduced by the polyphosphate.
 2. Adentifrice composition according to claim 1 wherein the polyphosphate ispresent in an amount of from about 1% to about 20% by weight of thecomposition.
 3. A dentifrice composition according to claim 2 whereinthe stannous ion is present in an amount of from about 3,000 ppm toabout 15,000 ppm.
 4. A dentifrice composition according to claim 3wherein the polyphosphate has a chain length of 6 or more.
 5. Adentifrice composition according to claim 4 wherein the polyphosphate isselected from the group consisting of linear polyphosphates having theformulaXO(XPO₃)_(n)X wherein X is sodium or potassium and n averages from about6 to about
 21. 6. A dentifrice composition according to claim 5 whereinthe stannous ion source comprises stannous chloride dihydrate.
 7. Adentifrice composition according to claim 5 wherein the molar ratio ofpolyphosphate anion to stannous ion is from about 0.5:1 to about 3:1. 8.A dentifrice composition according to claim 5 wherein the total watercontent is from about 2% to about 20%.
 9. A dentifrice compositionaccording to claim 5 wherein the polyphosphate has an average chainlength of about
 21. 10. A dentifrice composition according to claim 9further comprising materials selected from the group consisting offluoride ion sources, antibacterial agents, surfactants, thickeningmaterials, humectants, buffering agents, titanium dioxide, flavorsystems, sweetening agents, coloring agents, and mixtures thereof.
 11. Adentifrice composition according to claim 10 wherein the fluoride ionsource is selected from the group consisting of sodium fluoride, indiumfluoride, and sodium monofluorophosphate.
 12. A dentifrice compositionaccording to claim 10 wherein the thickening material is selected fromthe group consisting of carboxyvinyl polymers, carrageenan, hydroxyethylcellulose, sodium carboxymethylcellulose, sodium hydroxyethyl cellulose,gum karaya, xanthan gum, gum arabic, gum tragacanth, magnesium aluminumsilicate, silica and mixtures thereof.